Chronic kidney failure, also known as end-stage renal disease (ESRD), results in the build-up of waste toxins that affect organs and tissues throughout the body, and causes significant mortality. The most common cause of death in chronic kidney failure is cardiovascular disease that results from chronic inflammation. Infections are the second most common cause of death in patients with ESRD, suggesting that ESRD results in alterations to the immune system. Previous attempts to understand these changes in immune function have focused on the characterization of circulating immune cells from relatively small numbers of patients with ESRD. As such, these studies are limited by multiple different causes for the kidney failure, and it is often not possible to distinguish the effect of kidney failure frm the effects of the dialysis used to replace kidney function. In order to gain a better understanding of the primary effect of kidney failure on immune function it may be valuable to use an experimentally reproducible model system. For this proposal, the well-established and reproducible mouse model of ESRD represented by 5/6 nephrectomy (SNx) will be used. In this proposal's first specific aim, macrophages, a key cell in the innate immune system, will be isolated from SNx and control mice. These macrophages will be examined in tissue culture to understand how chronic kidney failure primes the innate immune system to generate excess pro-inflammation. In the second specific aim, T- lymphocytes, the cell type responsible for directing immune responses, will be isolated from SNx and control mice, and examined in tissue culture to understand how chronic kidney failure alters adaptive immune responses. In the third specific aim, the immune systems of SNx and control mice will be challenged in vivo with the fungus Aspergillus fumigatus, which will serve as a model organism to probe pro-inflammatory immune responses that depend upon the coordinated activity of both innate and adaptive immunity. In all three aims, experiments will be conducted to isolate nuclear DNA from immune system cells to determine if the difference in their responses will be reflected in acquired modifications to their DNA (i.e. epigenetic alterations). The information gained from these studies is a first step in order to better understand how chronic kidney failure alters immune function, and how these alterations contribute to the high mortality in ESRD. Ultimately, it is hoped that these studies will lead to the development of new methods to reset immune responses in ESRD, and help to prevent both cardiovascular disease and lethal infections.